Time filter

Source Type

Pircher M.,ABES Consulting International GmbH | Wagner J.,ABES Consulting International GmbH | Lechner B.,Kompetenzzentrum Das virtuelle Fahrzeug Forschungsgesellschaft mbH | Kammersberger A.,Amt der Steiermarkischen Landesregierung
Life-Cycle and Sustainability of Civil Infrastructure Systems - Proceedings of the 3rd International Symposium on Life-Cycle Civil Engineering, IALCCE 2012 | Year: 2012

An investigation of the damage caused by road traffic was performed on a reinforced concrete bridge called the Weizbach Bridge in the province of Styria in Austria. This study was undertaken with a focus on the determination of the damage induced by heavy vehicles in relation to the damage caused by average everyday traffic. A damage model based on fatigue of reinforcement bars was employed. Heavy traffic was shown to cause a disproportionate high portion of the overall damage on this bridge. The Weizbach Bridge is a three-span span reinforced structure constructed in 1969 with spans of 10+20+10m and a double-Tee cross-section carrying two lanes. This bridge is due for rehabilitation in mid-2012, two years after completion of the described study. The rehabilitation brief had several objectives, one of them being the reduction of ongoing accumulating damage due to heavy traffic. The present paper reports on the findings of the damage study as well as the proposed measures to reduce traffic-related damage after rehabilitation.

Froehlich K.,Austrian Institute of Technology GmbH | Bimashofer G.,Austrian Institute of Technology GmbH | Fafilek G.,Kompetenzzentrum Das Virtuelle Fahrzeug Forschungsgesellschaft mbH | Pichler F.,Institute of Chemical Technologies and Analytics | And 2 more authors.
ECS Transactions | Year: 2016

The commercially available and widely used LP30 electrolyte was characterized via different methods to investigate thermodynamic and transport phenomena related to the salt concentration. Relevant electrolyte properties such as viscosity, conductivity, transference numbers, and diffusion coefficients of lithium ions were determined for different concentrations of conducting salt. The obtained parameters were used to set up an electrochemical model. The results show good reliability with highest ionic conductivity at 1 mol/l LiPF6 concentration. The proposed electrochemical model was simplified so that only transference numbers and conductivity are necessary for the parametrization of this electrolyte in the measured concentration range up to 2 mol/l LiPF6. © The Electrochemical Society.

Golubkov A.W.,Kompetenzzentrum Das Virtuelle Fahrzeug Forschungsgesellschaft mbH | Scheikl S.,Kompetenzzentrum Das Virtuelle Fahrzeug Forschungsgesellschaft mbH | Planteu R.,Kompetenzzentrum Das Virtuelle Fahrzeug Forschungsgesellschaft mbH | Voitic G.,University of Graz | And 5 more authors.
RSC Advances | Year: 2015

Thermal runaway characteristics of two types of commercially available 18650 cells, based on LixFePO4 and Lix (Ni0.80Co0.15Al0.05)O2 were investigated in detail. The cells were preconditioned to state of charge (SOC) values in the range of 0% to 143%; this ensured that the working SOC window as well as overcharge conditions were covered in the experiments. Subsequently a series of temperature-ramp tests was performed with the preconditioned cells. Charged cells went into a thermal runaway, when heated above a critical temperature. The following thermal runaway parameters are provided for each experiment with the two cell types: temperature of a first detected exothermic reaction, maximum cell temperature, amount of produced ventgas and the composition of the ventgas. The dependence of those parameters with respect to the SOC is presented and a model of the major reactions during the thermal runaway is made. © The Royal Society of Chemistry 2015.

Sommer M.S.,Institute of Electrical Measurement and Measurement Signal Processing | Hrach D.,Institute of Electrical Measurement and Measurement Signal Processing | Schweighofer B.,Institute of Electrical Measurement and Measurement Signal Processing | Cifrain M.,Kompetenzzentrum Das Virtuelle Fahrzeug Forschungsgesellschaft MbH
Procedia Engineering | Year: 2010

For modelling the porosity of the electrodes in a lithium-ion battery the electrode materials are described by spherical particles. With these particles the main chemical reaction, the diffusion of lithium into the electrodes, is described. Because the main reaction occurs at the surface of a particle a numerically efficient solver which is able to predict the correct surface concentration with only a few discretization points in the bulk is developed. The new algorithm is compared to a standard finite difference scheme with respect to accuracy, the number of discretization points used, and calculation time.

Stocker A.,Kompetenzzentrum Das virtuelle Fahrzeug Forschungsgesellschaft mbH | Brandl P.,Evolaris | Michalczuk R.,Evolaris | Rosenberger M.,Kompetenzzentrum Das virtuelle Fahrzeug Forschungsgesellschaft mbH
Elektrotechnik und Informationstechnik | Year: 2014

Industry 4.0 summarizes all technologies, trends and developments which serve to advance production plants. As the ICT industry acts as a major enabler, industry 4.0 is often perceived as computer engineered production, only. Besides this rather technocratic viewpoint of industry 4.0, a human-centred view is continuously emerging. Many experts expect the human knowledge worker to play a major role in so-called smart factories. Supporting human workers in production through providing them with decision-relevant information and knowledge via innovative end devices including wearables and head mounted displays is a central topic of research. This paper outlines feasible ICT-solutions for future production workers in the four use cases, personalized augmented operator, worker-centric knowledge sharing and management, self-learning manufacturing workplaces and in-situ mobile learning in the production. © 2014, Springer Verlag Wien.

Engelmayer M.,University of Graz | Wimmer A.,University of Graz | Pirker G.,University of Graz | Pemp B.,University of Graz | Hirschl G.,Kompetenzzentrum Das Virtuelle Fahrzeug Forschungsgesellschaft mbH
American Society of Mechanical Engineers, Internal Combustion Engine Division (Publication) ICE | Year: 2011

The development of low-emission combustion concepts for large Diesel engines requires a specially adapted methodology. In all phases of the development process, it is essential that appropriate tools are used so that an optimized solution can be found within a short time. This paper will describe the methodology used for developing combustion concepts for large Diesel engines. In general, the development of a combustion concept for Diesel engines comprises the definition of the system (e.g. combustion chamber geometry, injection system, EGR system and charging system) and the calibration of engine parameters (e.g. injection parameters, EGR rate, charge pressure, excess air ratio and valve timing) for an application and its emission scenario. In the present case, the main objective was to develop concepts for applications to comply with emissions standards according to EU Stage III B and US EPA Tier 4. To this end, the LEC has developed the LDM method (LEC Development Methodology). This method is based on the intensive interaction of simulation with experimental investigations on single-cylinder research engines. As part of this development methodology, 3D CFD simulation as well as 0D and 1D engine cycle calculation are employed. Another approach used to handle the complexity of the systems is Design of Experiments (DoE) for simulation and experimental work. While 3D CFD simulation is used to optimize the details of the combustion and pollutant formation processes in the combustion chamber, 0D and 1D engine cycle simulation is applied to select the concepts and to pre-optimize important engine parameters. One great advantage of 0D and 1D models is their short calculation time, which allows the investigation of a great amount of variations in parameters. In order to apply the methodology, it must be guaranteed that the results from tests on the single-cylinder engine (SCE) can be transferred to the multi-cylinder engine (MCE). Therefore, it is necessary that the boundary conditions of the SCE are comparable to those of the MCE. Not only the same thermal boundary conditions but also the same conditions at the beginning of the high-pressure cycle (charge composition, pressure and temperature) must be maintained. The SCE measurement results that are generated serve to verify and calibrate the simulation models and deliver the necessary boundary conditions for further simulations. All in all, the paper comprises an evaluation of the different simulation models used and the applied development methodology in order to optimize fuel consumption and to reduce the emissions of large Diesel engines. © 2011 by ASME.

Haigermoser A.,Siemens AG | Luber B.,Kompetenzzentrum das Virtuelle Fahrzeug Forschungsgesellschaft MbH | Rauh J.,Daimler AG | Grafe G.,3D Mapping Solutions GmbH
Vehicle System Dynamics | Year: 2015

Road and track irregularities have an important influence on the dynamic behaviour of vehicles. Knowledge of their characteristics and magnitude is essential for the design of the vehicle but also for comparable homologation and acceptance tests as well as for the planning and management of track maintenance. Irregularities of tracks and roads are regularly measured using various measurement technologies. All have advantages and weaknesses and require several processing steps. Characterisation of irregularities is done in the distance as well as in the wavelength domain. For rail irregularities, various distance domain description methods have been proposed and are in use. Methods have been analysed and compared with regard to their processing steps. Several methods have been analysed using measured irregularity and vehicle response data. Characterisation in the wavelength domain is done in a similar way for track and road irregularities. Here, an important issue is the estimation of the power spectral densities and the approximation by analytical formulas. For rail irregularities, periodic defects also play an important role. The use of irregularities in simulations requires various processing steps if measured irregularities are used, as well as if synthetic data are utilised. This paper gives a quite complete overview of rail irregularities and points out similarities and differences to the road. © 2015 © 2015 Siemens AG Austria.

Tomberger C.,Kompetenzzentrum Das virtuelle Fahrzeug Forschungsgesellschaft mbH | Dietmaier P.,University of Graz | Sextro W.,University of Paderborn | Six K.,Siemens AG
Wear | Year: 2011

A profound description of friction in wheel-rail contact plays an essential role for optimization of traction control strategies, as input quantity for railway simulations in general and for the estimation of wear and rolling contact fatigue. A multitude of wheel-rail contact models exists, however, traction-creepage curves obtained from measurements show quantitative and qualitative deviations. There are several phenomena which influence the traction-creepage characteristics: Mechanisms resulting from surface roughness, frictional heating or the presence of interfacial fluids can have a dominating influence on friction. In this paper, a new wheel-rail contact model, accounting for these influential parameters, will be presented. The presented model accounts for the interaction of an interfacial fluid model for combined boundary and mixed lubrication of rough surfaces with a wheel-rail contact model that additionally accounts for frictional heating. A quantitative comparison with measurements found in the literature is not conducted, since the exact conditions of the measurements are mostly unknown and parameters can easily be adjusted to fit the measurements. Emphasis is placed on the qualitative behavior of the model with respect to the measurements and good agreement is found. The dependence of the maximum traction coefficient on rolling velocity, surface roughness and normal load is studied under dry and water lubricated conditions. © 2010 Elsevier B.V.

Pircher M.,ABES Consulting International GmbH | Lechner B.,Kompetenzzentrum Das Virtuelle Fahrzeug Forschungsgesellschaft mbH | Mariani O.,Kompetenzzentrum Das Virtuelle Fahrzeug Forschungsgesellschaft mbH | Kammersberger A.,Amt der Steiermarkischen Landesregierung
Engineering Structures | Year: 2011

An investigation of the damage caused by road traffic on three reinforced concrete bridges was performed. This study was performed with a focus on the determination of the damage induced by heavy vehicles in relation to the damage caused by average everyday traffic. A damage model based on fatigue of reinforcement bars was employed. The stress cycles in the reinforcement bars were determined using measurements of the crack widths under traffic loading. Stress cycles were analyzed using the Rainflow Method and Miner's Rule was employed to gain a measurement for the damage. Monitoring systems were installed on each of the three bridges and operated for several weeks continuously to collect input data for the damage model. Computer software was developed to process the monitoring data in the sense of the damage model. The described methodology was developed and used for the first time in the described project. Heavy traffic was shown to cause a disproportionate high portion of the overall damage on all three bridges. The obtained results indicated that the damage caused by singular events, such as the passage of a heavy vehicle, in relation to the damaging effects of every-day traffic differed significantly between the considered bridges. For one of the bridges the greatest damage from singular traffic events was computed for passages of special transport vehicles. The same bridge was also found to display the highest damage by a single passage in relation to average everyday traffic. Passages of short and heavy trucks with four and five axles were identified as the most detrimental traffic events on the other two bridges. © 2011 Elsevier Ltd.

Kompetenzzentrum Das Virtuelle Fahrzeug Forschungsgesellschaft Mbh | Date: 2014-04-09

So as to make the co-simulation of subsystems of an overall system (1), which are reciprocally coupled by way of coupling variables (y_(1), y_(2)), real-time capable, a mathematical model (M) of the subsystems (TS1, TS2) which is valid at the current operating point of the overall system (1) is ascertained from input variables (x_(1), x_(2)) and/or measured variables (w_(1), w_(2)) of the subsystems (TS1, TS2) based on a method of data-based model identification and, from this model (M), the coupling variables (y_(1), y_(2)) are extrapolated for a subsequent coupling time step and made available to the subsystems (TS1, TS2).

Loading Kompetenzzentrum Das Virtuelle Fahrzeug Forschungsgesellschaft mbH collaborators
Loading Kompetenzzentrum Das Virtuelle Fahrzeug Forschungsgesellschaft mbH collaborators